Flame holder and fuel nozzle supporting mechanism for ram jet engines



Jan. 20, 1953 E. P. NEIKIRK ET AL 2,625,788

FLAME HOLDER AND FUEL NOZZLE SUPPORTING MECHANISM FOR RAM JET ENGINES 2 SHEETS-SHEET 1 Filed Dec. 15 1948 IMHII 5) w w T. E W fl mA T ma Jan. 20, 1953 E. P. NEIKIRK EI'AL 2,625,788

FLAME HOLDER AND FUEL NOZZLE SUPPORTING v MECHANISM FOR RAM JET ENGINES Filed Dec. 15, 1948 2 SHEETSSHEET 2 v INVENTORS 4% 6 @AA? 66/14, kg

THEIR ATTORNEYS.

Patented Jan. 20, 1953 UNITED STATS r OFFICE "FLAME "HGLDER AND FUEL NOZZLE SUP- PORTING MECHANISM FOR RAM JET ENGINES Edwin F. Neikirk, Ferguson, and John'lzo, Jr., Overland; Mm, assignors to McDonnell Aircraft (Zorpgoration, v St. "Louis, ,Mo., a corporation of Maryland Applicationllec.emben15, 1948 Serial No. 65,374

'11 Claims. (01. 60-3526) will take place over ,most of the cross sectional area thereof.

Another object of theinvention is to provide an improvedfiame holder and ,fuel distributing fixture for .a ram .jet engine.

Thisinvention consists of a tubular member whose. forward and rearward ends are contracted and in which a fuel distributing fixture is arranged whichsupports aplurality of nozzles whose orifices discharge-fuel outwardly toward the casing and slightly forwardly and which has a forwardly facing axially positioned nozzle provided .with an orifice larger indiameter than the orifice of the first mentioned nozzle and which .discharges fuelv directly into. the-air stream entering the tubular member. :The ;fuel distributing fixture is supported in the forward end of the tubular .member .by means of a flanged ring towhicha plurality-of circularly disposed arms-are secured which also function as flame holders, one end. of :each .arm being.

secured to the ring and-then inclined rearward- 1y and outwardly until their opposit or outer endscontact theinnersurface of the tubular member and aresecure'd thereto, the-arms being provided with a flat faceon the rearwardtside and with a rib on the --forwardsiole I for strengthening the arms.

In the drawings:

Fig. 1 is a longitudinal sectional View of'theimproved ram jet engine,

Fig. 2 is an end view thereof looking toward the left of Fig. l with parts brokenaway ,to show detail,

"Fig. 3 is a sectional viewfltaken along the-line 3- 3 ofiFig. 1,

Fig. 4 is a sectional view taken substantially along the line 4-4 of -Fig. 1,

Fig.5 is a sectional view takenalong the..line 5-501 Fig. 2; and

Fig. 6 is a sectional view taken along .thejline 6-6 of Fig. 2.

The invention isembodied. in" the structure set forth in the accompanying drawings in which the numeral 1 designates a longitudinally extended tubularmember whose forward and rear *2 ward ends are contracted to form "the intake and exhaust orifices 'for a ram jet engine- 'A bracket 2 is suitably fastened to the tubular member I for the purpose of securing'it'to' the outboard end of a rotor blade or other movable member. The forward end of the tubular member l is partially curled about and secured to ring 3 and a liner t has one end partially curled about and secured toring $3. This liner extends rearwardly and flares outwardly into-the tubular member 1 until it abuts the wall thereof Where it begi'nsto be substantially parallelytothelongitudinal axis of the tubular member. The'liner' substantially flush with the outer end of "liner 4 and are in contact with the'jliner. "The arm tabs I and outer end of ,thelinerjare then suitably secured to the tubular member'l'by means of rivets 8 or other suitablelmeans.

Each of the arms v6 is preferably made up of tworight angle bars 9, '9. Onei leg of each of the angular bars is placed in abutting relation and then secured together by welding or other suitable methods so that the resulting armhas" a flat face 1-0 on oneside thereof and a rib'H on the other. The arm is assembled so thatrib H faces forwardly and the flat facefll'f'faces' rearwardly. The rib ll strengthens or'stifiens' the. arm, thereby preventing its 'bendingduring operation.

The, fuel distributing head or fixture i2 is arranged in the diifusing chamber-just aft of the forward end of tubular member [and isremovably secured to the flanged ring'B'by screws". t3. A plurality of circumferentially arranged nozzles I4 is secured to the fuel distributing fixture it! in such a manner'that they discharge"-f uel"to*- ward the vinner surface. of liner ,4 and theifor-' ward end of the tubular member. .The' axially arranged nozzle [5,, secured to. fiXture [2, has an oriflce therein that is larger than the orifices in nozzles Id. The nozzle ['51 points forwardly and functions as a pilot jet for. the engine and discharges fuel directly in the air stream entering theqtubular member. Fuel is conducted toqthe' distributing fixture I 2, and supplied by it to the nozzles. i4 and I5, by means of a conduit 6"00111' nected thereto by a nipple I! and extends rearwardly from the fixture l2 and passes through the wall of the tubular member I so that it may be connected to a suitable source of fuel supply. The fixture is, therefore, a fuel supply means for the nozzles. The passageways through fixture l2 may be proportioned as to size in the same manner as the orifices in each of the nozzles, if so desired.

Initial ignition of fuel introduced into the engine is accomplished by a spark plug 18 connected to a suitable ignition coil. The spark plug is mounted in a V member l9 connected between two of the arms 6, the apex of the V facing forwardly.

Initial ignition of the engine is produced by moving the tubular member I at a predetermined speed through the air, after which fuel is introduced to the fuel distributing fixture l2 and thence discharged through nozzles 14 and I5 into the air. Air will be moving through the intake end of the tubular member at a high rate of speed and will carry the fuel back into the combustion chamber of the engine. At lower speeds the fuel discharge from nozzle IE will be distributed over a considerable area of the ram jet engine, but at higher speeds the discharge from nozzle I5 will flow back upon itself and be carried toward the central portion of the tubular member. The discharge from nozzles M will likewise be carried back into the tubular member; but since this fuel will be projected substantially radially outwardly and forwardly it will enter the outer portions of the interior of the tubular member. It is understood that initial ignition of this fuel will be accomplished by a spark plug l8 and thereafter the burning process will be continuous and the spark plug may then be disconnected from its ignition coil. The arms 6, in cooperation with the discharge from nozzles 14 and I5, contribute to obtaining optimum thrust from the fuel introduced into the tubular member. The discharge from nozzle l5 makes its contribution to the optimum output by supplying fuel to the more central portions of the engine tubular member I, and the nozzles l4 contributing their share by providing the fuel in the areas of the tubular member outwardly from the central portion toward the interior periphery thereof. Arms 6 modify the fuel distribution over the cross-sectional area of the tubular member so that said discharge is more uniformly distributed. The arms hold the flame and, by reason of their slope, carry some of the fuel toward the interior periphery of the tubular member where combustion will take place. The slope of the arms is so chosen that maximum combustion of fuel must occur within the combustion chamber of the engine.

In further explanation of the function of the arms 6, the ribs II are directed forwardly into the stream of air and fuel mixing in the inlet of the tubular member I defined by the forward portion of the liner 4. These ribs ll, because of their shape act to divide the air and fuel mixture into two paths of flow which is laterally outwardly in the general direction of the flanges forming the face l0. It is noted that certain of the arms 6 intervene or are located between the nozzles 14 and others are aligned with the nozzles. This is to cause the intervening arms 6 to divide some of the air streams which may not carry as much fuel backward from the nozzles as other of the streams and greatly assist in mixing the air and fuel of the various streams which are directly back of the nozzles. The alternate alignment of nozzles I4 and arms 6 is not to be taken as a limitation, but is just one arrangement which has been successfully operated. The arms 6 thereby create great turbulence of the air and fuel mixture and tend to more evenly distribute the mixture in the area surrounding the arms. Furthermore, the slope of the arms tends to hold the name in that area and move it near the inner periphery of tubular member I, so that the high velocity combustion (due to speed of motion of the engine and air speed) may be held or stabilized in the combustion area and flame prevented from reaching the exhaust area, thereby increasing the desired thrust effect obtained by the expansion of hot gases.

The output of the engine may be varied by replacing the distributing head l2 with one having a different number of nozzles thereon, changing the length OI the head or its axial position in the tubular member, providing different size oriflees in the nozzles and by changing the angle at which nozzles 14 are mounted on the head as well as by varying the slope of the arms.

What we claim is:

1. A ram jet engine comprising a tubular member open at its forward and rearward ends, and through which an air stream passes between the forward and rearward ends; a plurality of arms mounted in the forward end of said tubular member and diverging outwardly and rearwardly from a point on the longitudinal axis of said tubular member, each arm resisting air stream movement and having a trailing llat face and a ribbed forward face, the flat faces of the plurality OI arms creating turbulence in the zones adjacent the arms for holding flames in the forward end of said tubular member adjacent to and on said arms; a fuel supply fixture supported by said arm near the forward end of said tubular member on the longitudinal axis thereof; and a plurality of fuel nozzles mounted on said fixture forwardly of said arms adjacent to and within the forward end of said tubular member for directing fuel forwardly of said arms into said air stream, the fuel being carried by the incoming air stream into the turbulent zones adjacent said arms and directed outwardly toward the inner periphery of the tubular member by said diverging arms for burning, the flames being held on the arms and adjacent the inner surface of said tubular member.

2. A ram jet engine comprising a tubular member through which an air stream passes between an intake and exhaust outlet. a plurality of fuel nozzles mounted in said tubular member near the inlet end for directing fuel into the air stream; a source of fuel connected with said nozzles; and means for supporting said nozzles in said tubular member which includes aplurality of outwardly and rearwardly inclined flame holder arms diverging from a point on the longitudinal axis of the tubular member and disposed rearwardly of said nozzles and each having a forwardly projecting rib on the front side and a flat surface on the rear side,'the air stream with the fuel therein being swept onto said arms for burning, the edges of said arms ceived and discharged; a fuel distributing fixture 5, in said tubular member; means :for supplying fuel to saidfixture; means for supporting said fixture in the forward end of said tubular mem ber, said means including a plurality of arms connected -to said fixture and ,to the inner surface of said tubular membensaid arms diverging outwardly and rearwardly from said fixture, and eacharm being formed with laterally extendingflat rearward portions and a reinforcing rib-on the-forward side thereof extending into the air stream, the reinforcing ribs and flat portions of said arms directing the flow of airentering the tubular-member intodivergent streams to create turbulence and resistance to passage, the edges of the rearward portions constitutingthe flame holders for the engine; andaplurality of nozzles secured to said fixture and provided with discharge orifices, said nozzles. being disposed .in

the forward end of said tubular member for distive to the longitudinal axis of said tubular,

member, said arms being connected with said tubular member, each arm-having a rib projecting forwardly into the air stream and laterally directed flanges extending across the air stream at each side of said rib; and a plurality of fuel discharging nozzles on said fixture directing fuel into the flow of air entering at said'forward end of said tubular member, aid fuel mixing in said air stream and being swept rearwardly against said arms, said ribs andflanges of said arms dividing and holding the mixture of fuel and air adjacent thereto for combustion aft of said arms, the flame being held on said arms.

5. A ram jet engine comprising a tubular member open at the forward and rearward ends thereof to admit of the flow of air therethrough due to forward movement of said tubular member; a fuel supply fixture; a supporting means for said fixture positioning said fixture centrally of said tubular member near the forward open end thereof, said supporting means including a plurality of flame holder arms each connected to and extending rearwardly from said fixture and connected to said tubular member in an inclined position relative to the longtiudinal axis of said tubular member, each of said arms having a rib projecting forwardly into the air stream flowing through the tubular member and each arm having laterally directed flanges; a plurality of fuel discharge nozzles on said fixture angularly disposed relative to the longitudinal axis and discharging fuel against the air stream entering at the forward end of said tubular member to be swept back toward said inclined arms and directed by said inclined arms outwardly to a location near the inner periphery of said tubular member; and an additional axially disposed fuel nozzle in said fixture discharging fuel axially forwardly into the incoming air stream to be swept back centrally of said tubular member for combustion aft of said arms, the flame being held on the arms.

a 6. A ram' jetenginacomprisingastubular member open at the forward and rearward ends'theraof and through which an: air: stream'passes; a fuel supply fixture, 7 means for i supporting said fixture in said tubular member near the forward end thereof, said supporting 'means including arms extending radially outwardly and being rearwardly inclined relative to thetposition of said fixture, each arm having laterally directed flanges defining'a substantially 'flat rearward fac and each arm having arib facing into-the air. stream to. divide-the air, each armicreating turbulencein the area surrounding andfbetween said-arms; a fuel supply conduit connected to .said fixture; and aplurality of nozzles carried bysaid fixture and disposed forwardly of said .supporting'arms,

said nozzles being supplied withfuel'fromsaid fixture for discharge into the air stream to :be swept rearwardly for combustion in the turbulent area aft of said arms, the flame beingxheld-on said arms.

'7. A ram jet engine comprising a tubular'merrbber open at theforward andrearward ends thereof and through which an air streampasses; a fuel supply fixture; a supporting structure for said fixture locating the latter centrally of said tubular member near the forward end-.thereof,-said structure including flame holder arms connected to said tubular member and extending ininclined relation to the longitudinalzaxis of said tubular member to points relatively rearwardly of said fixture, said arms beingof non-streamlined cross section and creating turbulence in the area surrounding said arms rearwardly of said fixture; a plurality of nozzlescircumferentially arranged onsaid fixture to be-supplied with fuel thereby, said nozzles directing the fuel forwardly into the airstream to be swept rearwardly into said arms for burning in the turbulent area surrounding said arms; and an additional centrally located nozzle on said fixture receiving .fuel therefrom and directing the fuel forwardly against the incoming air stream centrally .of said tubular memher to be swept back into the central part of the turbulent area of the ram jet engine, the flame being held on said arms.

8. A ram jet engine comprising a tubular member open at the forward and rearward ends thereof and through which an air stream passes due to forward movement of the engine; a fuel supply fixture; a plurality of radially directed flame holder arms having inner ends supporting said fixture near the forward end of said tubular member and along the longitudinal axis thereof, said arms being fixed at their outer ends to the inner periphery of said tubular member in a zone space rearwardly of the inner ends and said fixture relative to the direction of movement of the air stream, each of said arms having flanges projecting laterally into the air stream to create a turbulence zone and impede passage of the air past said arms; and a plurality of nozzles on said fixture supplied with fuel therefrom to be directed into the incoming air stream over the area of the forward end of said tubular member, the fuel thus directed being swept rearwardly for combustion in the turbulent zone, said flame holder arms holding the flame for burning fuel aft of said arms.

9. A ram jet engine comprising a tubular member open at the forward and rearward ends thereof and through which an air stream flows; a fuel supply fixture; a plurality of flame holder arms radially directed from the longitudinal axis of said tubular member and having their inner ends supporting said fixture on said axis near the forward end of the tubular member and outer ends of the arms connected with the inner periphery of the tubular member, said arms having a nonstreamlined cross-section and having the outer ends thereof located relatively rearwardly of the inner ends so as to locate the arms across the air stream and distribute the air flow toward the inner periphery of the tubular member; and a plurality of nozzles spaced about said fixture on the forwardly facing portion thereof, said nozzles being supplied with fuel from said fixture for delivery forwardly into the incoming air stream over the area near said forward end of the tubular member, the fuel mixing with the air and being swept rearwardly for burning in the zone aft of said flame holder arms, the flames being held on said arms.

10. A ram jet engine comprising a tubular member open at the forward and rearward ends for the flow of air therethrough due to forward movement of the engine; a fuel supply fixture near the forward end of said tubular member; supporting means for said fixture locating said fixture on the longitudinal axis of said tubular member, said support means including circumferentially spaced radially extending and rearwardly inclined arms, said arms having surfaces offering resistance to the air flowing toward the rearward end of said tubular member to hold the flame of burning fuel aft of said arms, the flames beinglheld on the edges thereof; a plurality of nozzles on said fixture in circumferential spaced and forwardly directed locations, said nozzles directing fuel supplied from said fixture forwardly into the air stream to be swept rearwardly toward said arms; and an axially located, forwardly directed nozzle on said fixture in addition to the aforesaid nozzles and receiving fuel from the fixture and directing some of the fuel forwardly to be swept rearwardly to the more central area of said tubular member for burning aft of said arms, the flame being held on said arms.

11. A ram jet engine comprising a tubular member open at the forward and rearward ends for the flow of air therethrough due to forward movement of the engine; a fuel supply fixture in the forward end of said tubular member; supporting means for said fixture including arms connected to said fixture at the inner ends of the arms, said arms extending radially outwardly in rearwardly inclined relation to the longitudinal axis of said tubular member and having the outer ends of said arms connected with the inner periphery of said tubular member, said arms 10- cating said fixture on the longitudinal axis of said tubular member forwardly of said arms, and each arm having a ribbed surface facing the forward end of the tubular member and opposing the flow of incoming air creating turbulent resistance to air movement in the zone surrounding and aft of all of said arms; and a plurality of nozzles on said fixture to receive fuel therefrom and to direct the fuel forwardly into the incoming air stream at the forward end of said tubular member, the fuel mixing with the air and being swept rearwardly by the incoming air into the turbulent zone surrounding and aft of said arms for burning aft thereof, the flame being held on said arms.

. EDWIN P. NEIKIRK.

JOHN IZO, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,086,984 McTarnahan July 13, 1937 2,529,506 Lloyd et al. Nov. 14, 1950 FOREIGN PATENTS Number Country Date 593,071 Great Britain Oct. 7, 1947 863,928 France Jan. 6, 1941 

